Design of super-orthogonal space-time trellis codes based on trace criterion

A design of super-orthogonal space-time trellis codes （SOSTTCs） based on the trace criterion （TC） is proposed for improving the design of SOSTTCs. The shortcomings of the rank and determinant criteria based design and the advantages of the TC-based design are analyzed. The optimization principle of four factors is presented, which includes the space-time block coding （STBC） scheme, set partitioning, trellis structure, and the assignment of signal subsets and STBC schemes in the trellis. According to this principle, systematical and handcrafted design steps are given in detail. By constellation expansion, the code performance can be further improved. The code design results are given, and the new codes outperform others in the simulation.

Systematic Design and Coordination Acts of Ecological Security in Upper Yangtze River in China

In this paper, systematic design and act of eco-security is discussed as a focal point of conflict and unrest. The situation of ecosystem, the schematic framework of eco-security design, the main acts of ecosystem improvement, major difficulties and challenges have also been analyzed. The purpose of this study was to formulate the systematic framework of eco-security maintenance, to highlight systematic idea or philosophy of ecological rehabilitation and eco-security. A three-dimensional schematic model is applied to design the security of ecosystem. It was concluded that: 1) maintaining ecological security requires far better and sophisticated resource management skill and ecological improvement measures, and is also a continuing and multifac-eted task. It cannot be permanently accomplished by a single action and program; 2) at present, technical system and policy and law system dimensions of ecological security are not enough even in short; 3) development of ecological industries is beneficial to local economic development and ecosystem protection.

Research on the Teaching Evaluation System based on Feedback Tracking Technology under Cloud Computing Environment

In this paper, we conduct research on the teaching evaluation system based on the feedback tracking technology under the cloud computing environment. Teaching evaluation is an important work of teaching management department. According to the traditional mode of work, must first into classroom, through questionnaire survey, fill out a form scale, obtain first-hand teaching evaluation data, and then input the data into the computer, after check again the data statistics and analysis which is not efficient. To optimize the procedure, we use the cloud computing to assist finalizing the general evaluation steps which is innovative and meaningful.

Deriving invariant checkers for critical infrastructure using axiomatic design principles

Cyber-physical systems(CPSs)in critical infrastructure face serious threats of attack,motivating research into a wide variety of defence mechanisms such as those that monitor for violations of invariants,i.e.logical properties over sensor and actuator states that should always be true.Many approaches for identifying invariants attempt to do so automatically,typically using data logs,but these can miss valid system properties if relevant behaviours are not well-represented in the data.Furthermore,as the CPS is already built,resolving any design flaws or weak points identified through this process is costly.In this paper,we propose a systematic method for deriving invariants from an analysis of a CPS design,based on principles of the axiomatic design methodology from design science.Our method iteratively decomposes a high-level CPS design to identify sets of dependent design parameters(i.e.sensors and actuators),allowing for invariants and invariant checkers to be derived in parallel to the implementation of the system.We apply our method to the designs of two CPS testbeds,SWaT and WADI,deriving a suite of invariant checkers that are able to detect a variety of single-and multi-stage attacks without any false positives.Finally,we reflect on the strengths and weaknesses of our approach,how it can be complemented by other defence mechanisms,and how it could help engineers to identify and resolve weak points in a design before the controllers of a CPS are implemented.